Selection of a Suitable Soft Computing Model for Estimation of Soil Cation Exchange Capacity

2018 ◽  
Vol 49 (21) ◽  
pp. 2664-2679 ◽  
Author(s):  
Saeed Saadat ◽  
Javad Seyedmohammadi ◽  
Leila Esmaeelnejad
2004 ◽  
Vol 35 (1-2) ◽  
pp. 51-67 ◽  
Author(s):  
R. L. Mulvaney ◽  
S. A. Yaremych ◽  
S. A. Khan ◽  
J. M. Swiader ◽  
B. P. Horgan

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 1015
Author(s):  
PW Moody

Krasnozems (Ferrosols) characteristically have high contents of citrate-dithionite extractable Fe and moderate to high contents of clay throughout the profile. They typically have low cation exchange capacity (2-20 cmolc kg-1), high P sorbing ability, and a significant anion exchange capacity at depth. The chemistry of krasnozems is dominated by the variable charge characteristics of the organic matter and the oxy-hydroxides of Fe and Al which occur in the predominantly kaolinitic clay fraction. The effects of surface charge characteristics, organic matter, and extractable iron and aluminium on the cation and anion exchange capacities, P sorbing abilities and pH buffer capacities of Australian krasnozems are reviewed. A selection of reports of nutrient deficiencies and toxicities in these soils is presented and briefly discussed. Published data on the chemical composition of the soil solutions of krasnozems are reviewed. Data from a suite of paired (undeveloped and developed) krasnozem profiles from eastern Australia indicate that exchangeable Ca and Mg, effective cation exchange capacity (ECEC), pH buffer capacity (pHBC) and total N decrease significantly (P < 0.05) in the A horizon following development, while exchangeable K, ECEC and pHBC decrease (P < 0-05) in the B horizon. The decreases in the A horizon are shown to be a direct consequence of the decline in organic matter which occurs following development. Because of the crucial role that organic matter plays in the chemical fertility of krasnozems, they are less likely to maintain their fertility under exploitative conditions than other productive clay soils such as Vertosols. It is concluded that the sustainable use of krasnozems will depend on maintenance or enhancement of organic matter levels, maintenance of surface and subsoil pH by regular application of amendments, minimization of erosion, and replacement of nutrients removed in harvested products.


1971 ◽  
Vol 51 (3) ◽  
pp. 405-410
Author(s):  
A. K. Ballantyne

Leaching a silt loam soil (cation exchange capacity 23 meq/100 g) with water containing increasing rates of potassium dust (KCl) indicated that high levels adversely affected germination and yields of wheat as well as response to fertilizer. Germination was greatly reduced by the treatment with 22.4 metric tons per hectare and nearly eliminated by 44.8 tons. The 44.8-ton/ha treatment also greatly reduced the yield of grain, but straw weights were affected very little by increasing rates of potassium dust. Response to fertilizer was also reduced by 22.4 and 44.8 tons. The exchangeable Ca and Mg decreased and K increased as increasing amounts of K dust were leached through the soil. The 44.8-ton treatment decreased the exchangeable Ca from 56.0 to 24.9% and the Mg from 21.2 to 4.9%, and increased the K from 7.2 to 51.9%. It would appear that K salts can be added to the soil, without any adverse effects, until the exchangeable K is increased to about 30%. With the soil under study this took more than 11.2 tons per ha (5 short tons/acre). The application of dolomite ameliorated the effect of excess K.


2017 ◽  
Vol 135 ◽  
pp. 242-251 ◽  
Author(s):  
Jalal Shiri ◽  
Ali Keshavarzi ◽  
Ozgur Kisi ◽  
Ursula Iturraran-Viveros ◽  
Ali Bagherzadeh ◽  
...  

CATENA ◽  
2017 ◽  
Vol 158 ◽  
pp. 194-200 ◽  
Author(s):  
Yones Khaledian ◽  
Eric C. Brevik ◽  
Paulo Pereira ◽  
Artemi Cerdà ◽  
Mohammed A. Fattah ◽  
...  

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